Stainless Steel Information
Stainless Steel is a steel alloy with a minimum of 10.5% to 11% chromium. Chromium improves corrosion resistance by forming an oxide to the steel. Other elements are used to affect stainless steel such as nickel, nitrogen, molybdenum and titanium. Using these elements forms different crystal structures that can improve certain applications such as machining, welding and shaping.
304 is the most commonly used type of stainless because it’s the best value and can be used in a wide range of application. 304 SS is classified as a low carbon austenitic alloy with a maximum carbon content of 0.03%.
316 is the second most popular type of stainless. It’s more expensive but it provides better corrosion resistance than 304 because of the addition of molybdenum. 316 is used in food grade products as well as surgical, pharmaceutical, marine and acidic applications.
321 is a titanium bearing stainless steel. It is made by adding titanium to 304 SS. The addition of titanium stabilizes the metal against carbide precipitation during welding. It also improves shaping and forming qualities.
There is a widely held myth that stainless steel is not magnetic. Part of that myth is that low grade stainless is magnetic and higher grades are not.
There are many factors that determine magnetism in stainless. A piece of stainless steel stock can start out as non-magnetic but the manufacturing process of turning that stock into a part, such as a fitting, can cause the part to become slightly magnetic. The process of cold working the metal, casting, or welding can slightly change the crystal structure of the metal. Even though the metal has become slightly magnetic it has not changed the corrosion resistance.